Fastener driving means



D 1969 N. R. DOHERTY 3,482,754

FASTENER DRIVING MEANS Filed July 11, 1966 5 Sheets-Sheet l NORMAN R.DOHERTY d m/116 m ATTQRNEY N.R-DOHERTY FASTENER DRIVING MEANS Dec. 9,1969 5 Sheets-Sheet 2 Filed July 11, 1966 UVYQHVTOR. NORMAN R. DOHERTY'ATTORNEY Dec 9, 1969 N. R. DOHERTY FASTENER DRIV ING MEANS Shets-Sheet sFiled July 11, 1966 INVENTOR. NQRMAN R. DOHERTY ATTQRNEY Dec. 9, 1969 N.R. DOHERTY FASTENER DRIVING MEANS 5 Sheets-Sheet 4 w wwN o QN WNN m mi mQ Q Q um wm. R,

I N VEN TOR. NORMAN R. DOHERTY ATTORNEY Dec. 9, 1969 N. R- DOHERTYFASTENER DRIVING MEANS 5 Sheets-Sheet 5 Filed July 11, 1966 INVENTOR.NORMAN R. DOHERTY LMM/ g ATTORNEY United States Patent T 3,482,754FASTENER DRIVING MEANS Norman R. Doherty, Farmingdale, N.Y., assignor toElectric Stapler Corporation, Farmingdale, N.Y. Filed July 11, 1966,Ser. No. 564,227 Int. Cl. B27f 7/22 US. Cl. 227131 18 Claims ABSTRACT OFTHE DISCLOSURE An electrically operated fastener driving tool havingreadily releasable head housing and supply track which permitsinterchange of channels for the supplying of different sized fastenersusing a single basic power head.

This invention relates to fastener driving tools and particularly,although not limited thereto, to an electrically operated staple drivingtool having interchangeable means for accommodating fasteners of varioussizes and shapes.

In the electric stapler and tacker art there are many examples ofcumbersome and unwieldy machines. Generally, such devices employed asolenoid and linkage to move the driver of a conventional tool designedfor hand powered operation.

In my copending application entitled Electric Fastening Tool, filed Nov.24, 1965, and assigned Ser. No. 509,475, now Patent No. 3,347,441, thereis disclosed a compact, lightweight, easily handled device whichovercomes many of the drawbacks of the prior art. Typical of such priorart deficiencies was the excessively large solenoid employed foractuation of the fastener driving element. Accordingly, high input powerwas required and this resulted in an excessive heat output when the toolwas used for even a short period of time. A second and even moreimportant characteristic of many of the prior art devices was thecoaxial positioning of the driver blade with respect to the armature ofthe solenoid. Because of this construction the operator could not worktoo closely to an obstruction, such as the wall. Of necessity, thedriver blade would have to be spaced from the obstruction by at leasthalf the width or diameter of the solenoid plus the thickness of thetool housing. Further, the prior art devices did not readily adaptthemselves to interchangeability. That is, they could not readily acceptstaples having different widths, lengths or gauge wire.

The device described in my aforesaid copending application employs achassis which carries a drive system comprising a unique solenoid, atrigger switch connected to a solid state control for power input to thesolenoid. The circuit shown in my copending application, or othersuitable SCR pulse circuits, may be employed. When actuated by thetrigger switch, the circuit admits from A1 to /2 cycle of AC). powerfrom the line to the solenoid.

A staple driving blade is removably mounted on a' cantilevered arm thatis integral and movable together with the solenoid armature. In additionto the interchangeability of the driver blade, the combination staplesupply magazine and head housing is also interchangeable. Cover membersare provided which also serve as a handle. As in my aforementionedcopending application, all of the interchangeability features to bedescribed more fully hereinafter are achieved without recourse toremovable fasteners.

Among the features of the apparatus not disclosed or specificallyclaimed in my aforesaid copending case are:

(1) The retaining tabs used to capure the locking clips are formed onthe head housing as opposed to the prior construction where these tabswere positioned on the staple channel. A more rugged and reliable toolis pro- 3,482,754 Patented Dec. 9, 1969 vided by means of the presentconstruction. The locking clips also serve as a shock absorber againstthe force of the armature to maintain the components in contact. The useof resilient clamping means for securing the staple channel to the toolserves as a shock adsorber providing a more rugged and reliable tool.

(2) An improved bracket is used to mount the solenoid and the bearing ofan external spring return to the solenoid chassis.

(3) An improved bearing -for the spring return and improved connectionmeans between the spring return and the solenoid armature have beenprovided.

(4) A positive release latch is now included to permit easy separationof the components when the spring clip retaining the interchangeablecomponents is released.

(5) A unitized mounting block for the trigger and switch assembly isemployed.

(6) An interlock is provided for the trigger so that the tool cannot beused when the interchangeable components are removed.

(7) As an optional feature several slots have been eliminated from thesolenoid housing in order to make the interior of the solenoid lesssusceptible to contamination. The optional construction also makes thesolenoid casing stronger.

(8) The interchangeable head housing is provided with a critical insidewall location that is variable from unit to unit in accordance with thegauge of staples and particular driver blade that is being used.

(9) Means are provided for releasably holding the channel retainingspring clip in a retracted position when the release latch is depressedand the interchangeable components are removed.

(10) A shield substantially covering the armature arm slot in thesolenoid housing is also included. The shield serves the additionalfunction of providing a low friction bearing surface for the driverblade.

The present invention will be described in connection with means fortacking wire staples. However, it is to be clearly understood that thebasic concept of this invention may be applied to staple clinching toolsas well, and, in addition, to tools for driving other fasteners, such asnails, brads, tacks, pins and the like.

Accordingly, it is an object of the present invention to provide animproved, lightweight, hand-held, electrically driven staple fasteningtool.

It is another object to provide an improved bearing member for thesolenoid return spring.

It is a further object to provide a release mechanism for theinterchangeable components.

Yet another object is to provide improved unitized mounting means forthe trigger and switch.

It is a further object to provide an improved solenoid housing.

A further object is to provide an interlock between the trigger and therelease mechanism of the fastening tool.

Yet another object is to provide an improved mounting bracket for thesolenoid.

A particular object of the invention is to provide a combined shield andbearing surface for the solenoid housing and driver blade, respectively.

Yet another object is to provide simplified spring clip retaining meansfor the solenoid return spring bearing block.

It is of course an object of this invention to include all of theaforementioned objectives in an improved electrically operated fasteningtool that has interchangeable components, such as a staple-drivingblade, a head housing and a staple supply channel.

A feature of this invention is that the interchangeability is achievedwithout recourse to conventional fasteners such as screws, nuts, rivets,etc.

An additional feature of this invention is the provision ofinterchangeable staple supply chambers and driving blades dimensioned inaccordance with the size of the staple being used.

Another feature of this invention is the fact that the power package,which represents the most expensive portion of the tool, is common to awide range of supply magazines and driver blades.

Another object of this invention is to provide a low cost yet ruggedstaple driving tool that has interchangeable components in aself-contained power package.

A particular feature of this invention, is to provide a single powerpackage and housing together with a set or range of driver blades andstaple supply magazines, the total cost for which is far less than forprior art devices having a comparable range.

An important feature of this invention is the use of a driver bladeremovably disposed on a cantilevered arm of a solenoid armature havingan elongated coaxial bearing and an external return spring.

These and other features, objects and advantages of the invention will,in part, be pointed out with particularity and will, in part, becomeobvious from the following more detailed description of the invention,taken in conjunction with the accompanying drawing, which forms anintegral part thereof.

In the various figures of the drawing like reference charactersdesignate like parts.

In the drawing:

FIG. 1 is a plan view of the present invention;

FIG. 2 is a side elevational view, partly in section, taken along line22 of FIG. 1;

FIG. 3 is an exploded sectional side elevational view showing theinterchangeable components separated from the main housing;

FIG. 4 is a plan view of the combination head housing and supply track;

FIG. 5 is a fragmentary sectional side elevation view of the forwardportion of the combination head housing and supply track;

FIG. 6 is a detail plan view of a typical nose piece used with thisinvention;

FIG. 7 is a vertical sectional view taken through the solenoid alongline 77 of FIG. 2;

FIG. 8 is a plan view of the solenoid mounting bracket;

FIG. 9 is a side elevational view of the solenoid mounting bracket;

FIG. 10 is a front view of the bearing member for the solenoid springreturn;

FIG. 11 is an exploded plan view of the bearing memher and retainingclips for the solenoid spring return;

FIG. 12 is a sectional side elevational view of the release latchassembly and trigger interlock mounted in the solenoid chassis;

FIG. 13 is a plan view of the release latch assembly and triggerinterlock;

FIG. 14 is a fragmentary plan view of the forward end of the releaselatch;

FIG. 15 is an elevational view, partly in section, of an alternativeform of solenoid housing;

FIG. 16 is a plan view taken along line 16-16 of FIG. 15;

FIG. 17 is a schematic front view of a driver blade together withoutlines in phantom of a range of driver blades of other widths whichare examples of the interchangeability feature of the present invention;

FIG. 18 is a fragmentary schematic side elevational view in section of ahead housing showing in phantom outline other head housingconfigurations which are suitable for use with this invention;

FIG. 19 is a fragmentary sectional view, taken along line 1919 of FIG. 3illustrating clip retaining means;

FIG. 20 is a fragmentary front elevational view of the solenoid housingtogether with the combined dust shield and bearing surface;

FIG. 21 is a fragmentary side elevational view of the componentsillustrated in FIG. 20;

FIG. 22 is a detail elevational view of the switch and trigger mountingblock;

FIG. 23 is a plan view taken along line 2323 of FIG. 22; and

FIG. 24 is a vertical sectional view taken along line 2424 of FIG. 22.

Referring now to the drawings, and in particular to FIGS. 1, 2 and 3,there is shown the present invention comprised of an improved,electrically powered fastener driving tool 30 having interchangeablecomponents. The tool housing is made in two matching halves 32a and 32bwhich may be metal castings or which may be made of any of the presentlyavailable high strength plastics. It should be noted that the toolhousing is not a structural member and serves only the functionalpurpose of retaining the internal components and providing handle means.

The front portion 34 of the tool housing is substantially cylindrical incross section in order to accommodate solenoid 36 and several of thecomponents assciated therewith. Midportion 38 of the tool housingdefines a hollow hand-gripping area that includes an internal, snapaction type switch 40 and an electronic power package 42. An SCR controlcircuit designed to deliver a fraction of a cycle of electricity from anAC power source is used as the power package. Rear portion 44 isprovided with an opening that admits a line cord 46 adapted to beconnected to a suitable source of power (not shown).

Four screws 48 that traverse and are threadably secured in the twohousing halves are all that is employed to hold the housing partstogether. These are the only fasteners that are removed when eitherrepairs or maintenance requiring replacement of the internal componentsare to be made. However, it is not necessary to disturb screws 48 whencertain components are to be interchangd in order to permit the tool todrive fasteners having different basic sizes. In this connection itshould be noted that the present invention will be described as a stapletacker and, by definition, the width of the staples is the transversedimension between the staple legs. The length of the staple is thelength dimension of the legs and the gauge of the staples is determinedby the wire or material size used.

Tool 30 additionally includes a combination head housing and staplesupply track comprising a head housing section 52 integral with a supplytrack section 54. The combined sections are substantially L-shaped withthe head housing section and the supply track section individually beingU-shaped. Interlocking tabs 56 are provided on the opposed walls of theupper end of head housing section 52.

A hollow nose piece 58 is also provided at the lower end of the headhousing. It should be noted that the nose piece is selected inaccordance with the width and gauge of the staples which, as they areurged to a forward position, are ejected through slot 60 formed in thetransverse wall 62 of the nose piece. Spaced parallel legs 64 extendrearwardly of the head housing and are welded to the spaced legs of theU-shaped supply track section 54. Depressions are inwardly formed onlegs 64 to aid in the welding assembly. The nose piece is in turn weldedat its rearwardly extending legs 65 to the inside surface of theupwardly extending legs of the supply track section, thus making for avery rigid and substantialy damage proof subassembly.

Supply track section 54 is comprised of a transverse web 66 and a pairof spaced, parallel legs 67. An elongated staple guide bar 68 is rigidlysecured to the transverse web of the supply track 54. The staples slideon bar 68 and are urged towards the forward, dispensing end of the toolby a spring biased pusher member 70 removably captured in a notch 72 atthe rearward end of the guide bar. As with the nose piece, the stapleguide bar is selected as part of the head housing and supply trackassembly in accordance with the width of the staples being driven.

Locating slots 74 and 76 in the side walls 67 of the staple supply trackcooperate with pins 78 and 80, respectively, extending laterally from anupwardly facing U-shaped support chassis 82 that is a permanent ornonchangeable element of the standard tool. By being nestinglypositioned within the staple supply track the bottom transverse surfaceof chassis 82 acts as a cover therefor and assures that the staples areslidably seated on the guide bar.

Chassis 82 also serves several other very important functions asfollows:

(a) Chassis 82 has the solenoid secured thereto;

(b) Chassis 82 loosely supports, in a pivotal manner, the retaining clipfor the interchangeable components;

-(c) The channel formed by chassis 82 supports the new release latch;

(d) The channel formed by chassis 82 supports the new trigger interlock.

A nut 84 is welded to the forward end of chassis 82 on which solenoid 36is mounted. A central non-magnetizable support shaft 86 extends throughthe solenoid case. The upper end 87 of the shaft is external of thesolenoid case while the lower end 88 is threadably secured to the nut.The solenoid case, comprised of ferromagnetic lower and upper sections100 and 102, respectively, includes a wire wound coil 104 and anarmature 106 biased by an external spring 108. An elongated,self-lubricating magnetizable bearing 110 is press fit into the centralbore of the armature and supports and guides shaft 86. The solenoid coilis electrically connected to the power package 42 by means of two leads(not shown) extending outwardly from lower case section 100. Amagnctizable coil cover 112, having a central aperture 114 to slidinglyreceive the body of the armature 106, is interposed between the lowerand upper case sections.

Armature 106 is provided with resilient, shock-absorbing means 116 and117 in the form of annular rings. In the lowermost position of thearmature, ring 116 resiliently abuts the top surface of cover 112. Inthe uppermost position of the armature, ring 117 resiliently abuts theinside top surface of the solenoid case. The upper, yoke-like portion118 of the armature includes an arm 120 integral therewith. The armaturearm extends outwardly from the body of the armature through a verticalslot 122 in the forward end of the upper solenoid case section. Arm 120releasably supports the driver blade 124 in sliding relationship withthe U-shaped portion of the head housing section 52. As is shown in FIG.3 and FIG. 17, driver blade 124 includes an aperture 126 in which thearmature arm is removably disposed and a pair of rearwardly extendingears 128 at the upper end thereof. Bars 128 are arranged to slide on thesolenoid case during movement of the armature. The lower end 130 of thedriver blade engages and ejects the staples. The width of the lower endis dimensioned in accordance with the width of the fastener beingdriven. Dimension a indicates the width of the driver blade used withthe widest staple, dimension a indicates the width of the driver bladeused with the narrowest fastener and dimension a" is used toschematically represent the width of all driver blades between thewidest and narrowest. It is also contemplated to fabricate the driverblade from a non-magnetic material, for example stainless steel, tominimize the pull-in created by the solenoid when it is energized. Inaddition, the upper solenoid case section includes two opposed slots 132that permit passage of laterally disposed armature extensions 134 andthe externally positioned armature return spring 108 secured to theextensions by means of cotter pins 136.

Spring clip 138 is substantially U-shaped and has a transverse,connecting portion 140 extending across chassis 82. The clip ispositioned below the solenoid case and is loosely disposed in chassisslots 83 while still being permitted free pivotal motion. Rearwardlyextending legs 142 of the spring clip are bent slightly to indirectlybear against the under side of the solenoid case at 144. The rearwardends of spring clip legs 142 are positioned about the laterallyextending ends of transverse pin 78. In this manner and in cooperationwith pin 80 and slots 76, the combination head housing and supply trackis removably carried by the tool housing.

The foregoing components, particularly the solenoid and the method ofinterchanging the various parts, are structurally and functionallydescribed in greater detail in my copending application. The severalimprovements thereto will not be separately described.

(I) RETAINING TABS (FIGS. 2, 3, 4, AND 7) A pair of clip retaining tabsa and 15012 are formed integrally with the head housing by bendingoutwardly the top edge of legs 64 in the area directly beneath thesolenoid case. Whereas, my prior construction provided similarlyfunctioning tabs on the fastener supply track, the illustrated structurehas the advantages of being more rugged and durable because a heaviergauge metal is used in the head housing portion. As before, legs 142 ofspring clip 138 are disposed below and bear upwardly against the tabswhen the tool is completely assembled. An important feature to be notedis that the spring clip 138 acts as a shock absorber since it isresilient and bears against the tabs 150a and 15% of the head housing.The impact of the solenoid at the extremes of its stroke is taken up bythe springs. The components are thereby prevented from separating duringusage of the tool, thus adding to the life and reliability of thedevice.

(II) SOLENOID MOUNTING BRACKET (FIGS. 2, 3, 7, 8, 9, AND 10) Instead ofthe stepped bracket used in the past to retain the solenoid and the headhousing, I now propose to use a substantially flat bracket 152 having anaperture 154 through which the central support shaft passes. A pair ofnotches 156 are formed at the forward side edges of the bracket toaccept head housing tabs 56 when the interchangeable components are alllocked in place. Brackof 152 also has a downwardly extending key portion158 at its rearward end, key 158 being positioned in a slot 160 at therear of the upper solenoid case section to prevent rotation thereof. Oneof the four screws 48 passes through aperture 162 in lip 158 wherebyboth the bracket and the solenoid case are rigidly secured. A second key164 is also formed on the rearward end of the bracket 152, the secondkey being arranged to cooperate with the trigger and switch mountingblock. Finally, two pairs of spaced notches 166 are also provided in theside edges of the bracket for a purpose that will now be explained.

(III) ARMATURE RETURN SPRING BEARING BLOCK (FIGS. 2, 7, 10, AND 11) Animproved bearing member 170 is now provided to guide the externalarmature return spring 108. Bearing 170, which preferably is a lowfriction plastic such as Teflon, Delrin, etc., has a flat bottom surface172 arranged to rest on the top of bracket 152. The block issubstantially semicircular in transverse cross section and has acentral, arcuate groove 174 dimensioned to receive the midportion ofspring 108. As described above, the ends of the spring are secured tooppositely directed extensions 134 of the armature. A pair of arcuatespring clips 176 extend over the top of the bearing member and haveinwardly turned ends 178 positioned beneath the bracket so that thebearing member is securely held in place. Grooves 180 in the blockreceive the central portion of the clips while notches 166 receive theinwardly turned ends of the spring clips.

7 (IV) RELEASE LATCH (FIGS. 1, 2, 3, 12, 13, AND 14) Release latch 181is in the form of an elongated apertured lever 182 that is pivotallymounted in the central portion of chassis 82 by means of a transversepin 184 extending between the walls thereof. A plate 186 having anaperture therein is welded to lever 182. Spring member 188, which isserpentine in shape, is disposed about pin 184 and bears against lever182 at one end and the chassis 82 at the other end. The spring 188normally biases the lever to the unloaded position. When the tool isfully assembled legs 67 of the supply track 54 bear upwardly againstears 200 formed integrally with the forward end 202 of lever 182. Ears200 extend laterally through elongated slots 204 in each spaced leg ofchassis 82. When the tool is fully assembled, the spring 188 is loaded.After the spring clip 138 is removed from the ends of pin 78, therearward end 206 of the release latch is pressed inwardly. This causesthe loaded spring 188 to urge ears 200 downwardly against legs 67 of thestaple supply track 54, thus releasing interlocking tabs 56 from notches156 in bracket 152. The combination head hous ing and supply track maythen be removed as a unit from the tool, leaving the driver bladecompletely exposed and accessible.

(V) TRIGGER AND SWITCH MOUNTING (FIGS. 2, 3, 22, 23, AND 24) Aninsulating mounting block 210 is used to mount both the trigger and theswitch in the tool housing. The downwardly extending body 212 of block210 is positioned between spaced, upwardly extending tabs 214 integralwith chassis 82. At its forward end body 212 includes a vertical channel213. Pin 216 is disposed in registered apertures 218 and 20 in the tabsand body portion 212, respectively. Second key 164 on the rearward endof solenoid mounting bracket 152 fits into a notch 222 on the top of theblock 160 and, in combination with pin 216, prevents movement of theblock.

Trigger 224 is pivotally mounted at one end on a second pin 226 that isdisposed in aperture 228 and extends outwardly from each side of block210. The inner end of a plunger 230 is slidably positioned in bore 232of the block body, while the outer end of the plunger rests on the freeend of the trigger. Compression spring 234 normally biases the plungerand the trigger away from the switch contact button. A second coaxialplunger 236 is also slidably mounted in bore 232 and is biased withrespect to the first plunger by a second spring 238. It will be seen inFIG. 24 that the lower end of the second plunger and the second spring238 are disposed in bore 240 of the first plunger. Wall 242, integralwith block 210, is used to mount the switch. For ease of manufacture,pins 184, 216 and 226 are all the same diameter and length.

v1 TRIGGER INTERLOCK (FIGS. 2, 3, 12, AND 13 In order to preventinadvertent usage of the tool when the head housing and supply track areremoved, interlock means are provided that disable the trigger at thattime. An elongated, vertically positioned lever 244 is linked at itsbottom end 246 to the forward end 202 of the release latch 182 and isarranged for vertical sliding movement between the confronting surfacesof the solenoid housing and the switch mounting block. Lever 244 isdisposed in vertical channel 213 provided in the switch mounting block.A pair of spaced ears 248 extend rearwardly from the top of lever 244.When the tool is fully assembled, the forward end of the release latchis in an elevated position and so is lever 244. The ears 248 aretherefore clear of the area about which the trigger pivots. However,when the head housing and supply track are disassembled, the forward end202 of the release latch 180 and the vertical lever 244 are both biaseddownwardly by spring member 8 188. In this condition ears 248 abutspaced latches 250 formed on the trigger and thereby prevent anymovement thereof. The tool will remain locked until legs 67 of thestaple supply track 54, when assembled, urge the forward end of releaselever 182 and the upper end of interlock lever 244 into an upwardposition.

v11) IMPROVEMENTS IN SOLENOID HOUSING (FIGS. 15 AND 16) As analternative construction, the opposed slots in the upper solenoid casesection may be almost entirely eliminated. This structure minimizes thelikelihood of loose staples or other such contaminants that may be inthe immediate work area from reaching the interior of the solenoid andthereby interfering with the action of the armature or shorting thecoil. The upper case is formed with a pair of opposed ribs definingdepressions 252 on the inside thereof. The depressions providesufiicient clearance for the portions of the armature that are securedto the return spring. All that is required is a pair of openings 254through which the spring ends may move when the armature travels betweenthe extremes of its stroke. It will be evident that the size of theopenings in the sole noid case has been substantially reduced. Where thestructure is otherwise comparable to the previously describedembodiment, primed reference characters are used.

(VIII) HEAD HOUSING IMPROVEMENT (FIG. 18)

Instead of using a single head housing for all gauge fasteners andutilizing a spring to maintain the driver blade against the inside ofthe transverse wall thereof, an alternative structure is contemplated. Ahead housing 256 is selected whereby the position of the forward wall258 will assure that the driver blade is directly over the forwardmostfastener in the supply track. Dimension b is used to indicate therearwardmost position of the wall 258, dimension b is used to indicatethe forwardmost position of wall 258 and dimension b schematicallyrepresents all wall positions between b and b. In practice the positionof wall 258 may be very accurately deter mined by jogging or offsettingportion 260 during the die forming operation.

(IX) CLIP RETAINING MEANS (FIG. 3)

When the tool is disassembled and the combination head housing andsupply track is removed, spring clip 138 hangs downwardly. In order toprevent fouling of the spring clip, a vertically disposed notch 262 isprovided on the inside surface of each housing half at the bottom of theforward end thereof. Because of the resilient nature of the spring clip,its legs will tend to snap into the notches when the clip is in thedownward position. This will prevent the spring clip from beingunintentionally bent or forced forward which would make reassembly moredifficult.

(X) DUST SHIELD AND DRIVER BLADE BEARING (FIGS. 20 AND 21) In industrialapplications, an electrically powered tool such as has just beendescribed is subject to contamination of the internal components. If,for example, a loose staple, wood or metal chip or other debris shouldenter the solenoid when the parts are being interchanged, substantialdamage can be incurred. This problem can be avoided by the use of shieldmember 264. An aperture 266 in the shield permits it to be mounted onthe solenoid arm, thus substantially covering the slot in the solenoidcase through which the armature arm moves. Since the arm will be in theup position when the housing is opened the slot will be almostcompletely covered. The slot is uncovered only when the armature ismoving and, since the housing must be closed because of the interlock,the interior of the solenoid is well protected.

The shield serves another very useful function. Because the shield ismovable with the armature, the shield acts as a bearing surface betweenthe rear of the driver blade and the solenoid case. Teflon, Delrin orother similar low friction plastics are ideal for use as the shield.

Although not specifically illustrated, it is within the scope of thisinvention to provide an improved electrically operated stapler. To dothis an anvil is preferably pivotably mounted at the rearward end of thetool. Suitable means may be provided for locking the anvil in place whenit is desired to be used as a stapler, it being understood that theanvil is positioned beneath the forward end of the head housing. It isalso possible with the structure described hereinabove to make the anvilremovable, thus increasing the utility of the tool.

Having thus disclosed the best embodiment of the invention presentlycontemplated, it is to be understood that various changes andmodifications may be made by those skilled in the art without departingfrom the spirit of the invention.

What is claimed is:

1. In an electrically operated fastener driving tool, including a toolhousing, having a solenoid case containing a solenoid energizable by asuitable source of power, said solenoid case being secured inside saidtool housing, an arm secured to a spring biased solenoid armature, atrigger, trigger controlled switch means electrically connected to thesolenoid and the source of power, a fastener driver blade positionedexternally of the solenoid case and coupled to the armature arm, a headhousing, a fastener supply track removably secured to the tool housing,means to feed fasteners from the supply track to the path of said driverblade, and retaining means to releasably hold the head housing andsupply track on said tool housing, the improvement comprising:

a release latch mounted in said tool housing, said release latch havingan external, manually operable portion, and an internal portion wherebywhen said retaining means are released said internal portion of releaselatch displaces said head housing and supply track from said toolhousing.

2. The device in accordance with claim 1 including spring means normallybiasing said release latch to an unlatched position, said spring meansbeing in a loaded condition when the tool is fully assembled.

3. The device in accordance with claim 1 wherein said supply trackincludes a first upwardly facing U- shaped channel, there being furtherincluded an upwardly facing U-shaped chassis spacedly nested within saidfirst channel and rigidly secured to said solenoid, said chassis havingopposed, elongated slots in the upstanding walls thereof, said releaselatch being an elongated lever pivotally mounted intermediate the endsthereof in said chassis, to provide an inner end and an outer end, saidinner end of said lever having a pair of outwardly extending earspositioned in the slots of said chassis, said ears being arranged tobear against the upstanding walls of said first channel whereby whensaid external portion of said release latch is manually displaced, andsaid retaining means is released, said head housing and supply trackwill be separated from said tool housing.

4. The device in accordance with claim 1 wherein said improvementfurther comprises an interlock responsive to the movement of saidrelease latch, said interlock having means to engage and preventmovement of said trigger when said release latch is actuated.

5. The device in accordance with claim 4 wherein said interlock is aslidable elongated bar having one end in engagement and movable togetherwith said release latch, the opposite end of said bar having a tabarranged to engage and prevent movement of said trigger when saidrelease latch is actuated.

6. The device in accordance with claim 1 wherein said improvementfurther comprises an L-shaped head housing a first portion of which isdisposed directly beneath said solenoid, said first portion including apair of outwardly extending ears arranged to be engaged by saidretaining means when said tool is fully assembled.

7. The device in accordance with claim 6 wherein said retaining meansare resilient and in the assembled condition exerts a restraining forceacting to hold. the head housing and supply track in close contact withthe housing of said solenoid. I

8. The device in accordance with claim 1 wherein said improvementfurther comprises an insulating trigger block rigidly secured withinsaid housing, said trigger block having means for mounting said switch,a plunger member slidable therethrough, said plunger member having oneend thereof in contact with said trigger, the other end of said plungermember being positioned in opposition to the contact button of saidswitch, and spring means urging said plunger away from the switchcontact button, said trigger being pivotally mounted on said triggerblock.

9. The device in accordance with claim 8 wherein said trigger blockincludes a keyway and said tool includes a bracket secured to thesolenoid case, said keyway being arranged to receive a portion of saidsolenoid case bracket.

10. The device in accordance with claim 8 wherein said plunger member iscomprised of first and second coaxial sections, said first sectionhaving an axial bore receiving a portion of said second section, saidfirst section being biased with respect to said block by said springmeans, there being further included a second spring disposed in the boreof said first section, said second spring being arranged to bias saidfirst and second sections with respect to each other.

11. In a solenoid actuated fastener driving tool having a cantileveredarmature arm extending through the solenoid case and a fastener driverblade positioned externally of the solenoid case and coupled to thearmature arm, a shield member disposed on said solenoid arm andsubstantially enclosing the slot in the solenoid case through which saidarmature arm extends.

12. The device in accordance with claim 11 wherein said shield is a lowcoefficient of friction material and is disposed on said armature armbetween said driver blade and said solenoid case.

13. The device in accordance with claim 12 wherein said solenoid case ismagnetizable and said driver blade is made of a non-magnetic material.

14. The device in accordance with claim 1 wherein said improvementfurther comprises notches in the forward end of said tool housing, saidretaining means being captured in the notches when said head housing andsupply track are removed from said tool housing.

15. The device in accordance with claim 1 wherein said improvementcomprises a supply track disposed within and welded to said headhousing.

16. A fastener driving tool, including a tool housing, having a fastenersupply track and a head housing removably secured to the tool housingand retaining means to releasably secure the supply track and headhousing to the tool housing comprising:

a release latch mounted in said tool housing, said release latch havingan external, manually operable portion, and an internal portion wherebywhen said retaining means are released said internal portion of releaselatch displaces said head housing and sup ply track from said toolhousing.

17. In a solenoid actuated fastener driving tool having external biasingmeans for the armature thereof, a low coefficient of friction bearingblock supporting said biasing means, said bearing block including a pairof transverse notches on the top surface thereof and wherein there isfurther included fastening means disposed in said notches, saidfastening means having inwardly turned end portions arranged to securesaid bearing block to said solenoid.

18. In a fastener tool having a solenoid actuated driv- 1 1 12 er blade,an armature arm biased by an elongated com- FOREIGN PATENTS pressionspring, the armature arm extending outwardly of 66 991 5/1957 France thesolenoid case through a slot therein, a yoke member 1290:83O 3/1962France:

integral with said armature and means integral with said yoke to securethe ends of said armature spring, the im provement comprising opposed,outwardly directed rib o THERON CONDON Primary Exammer portions on thesolenoid case, said armature extensions HORACE M. V Assistant Examinerbeing enclosed by said rib portions during displacement thereof. US. Cl,X.R.

References Cited 10 227 109 UNITED STATES PATENTS 3,347,441 10/1967Doherty 227-131

